Rail or telescopic extension

ABSTRACT

A horizontal or vertical rail or telescopic extension of a cupboard element, a baking shelf or an oven door of a cooking or similar device. The extensions including at least one outer rail of bent sheet metal and a sliding rail of bent sheet metal, which partially surrounds the outer rail and can be displaced along the outer rail by an anti-friction bearing. The rail extension including an outer attachment rail which is connected to and reinforces the outer rail and/or a further attachment rail that is connected to and reinforces the sliding rail. The telescopic extension includes two interconnected rail extensions.

The invention relates to a rail extension or a telescopic extension forthe horizontal or vertical extension of an extendable element,especially a baking shelf of a cooker.

In known ovens it is usually possible to arrange the food on grids orsheets at various heights between underheat and overheat for whichpurpose guide rails for placing the grids or sheets are formed on theside walls of the cooking compartment. In order to achieve betteraccessibility and handling of the sheets or grids, extendable frameswith a baking shelf are known which are connected to the cookingcompartment by means of lateral guide rails or telescopic extensions andmake it possible to displace the baking shelf horizontally together withthe food.

Generic arrangements of baking ovens or cookers with rail or telescopicextensions are known, for example, from DE 198 17 499 C1 or from DE 10051 153 A1. In addition to cookers with front-opening doors, those withdownward-opening doors are also known in which the door can either beconfigured as downward-hinged or downward-extensible. Thus, for example,a cooker is described in DE 100 59 650 C1 in which a door for closingthe cooking compartment is constructed as a housing base which closesthe open underside of the oven housing and can be lowered vertically bymeans of guide elements.

Fairly long guide elements, rail extensions or telescopic extensionswhich can additionally be subjected to a bending load by relativelyheavy baking shelves, must be designed as sufficiently stable and as aresult are usually relatively voluminous. Telescopic extensions withrails made of bent sheet metal in some cases do not have the necessarystability and torsional resistance. An increase in the sheet metalthickness of the rails so that these can better withstand the loadswhich occur, would require new bending tools and larger presses tomanufacture the rails. With increasing sheet metal thickness, thebending radii necessarily also become larger whereby the geometry of therails varies accordingly. In some cases, therefore telescopic extensionswith rails made of cold-drawn solid material are used which can absorb ahigher load. However, such telescopic extensions have a relatively highweight and in addition, are expensive to manufacture.

It is the object of the invention to improve a known rail extension ortelescopic extension with regard to its stability.

This object is achieved with a rail or telescopic extension according tothe preamble of claim 1 according to the invention by additionallyinserted attachment rails. The attachment rails bring about asignificant stiffening for the same external dimensions whereby theextension can bear higher loads without any additional bending ordistortion occurring. The U-shaped attachment rails are inserted insideor outside already existing sheet metal profiles of outer or slidingrails which can be displaced with respect to one another and areconnected thereto. The external dimensions of the rail or telescopicextensions remain the same but the stability of the rails issignificantly increased. The attachment rails can be welded, riveted,screwed or glued to the base rails. The connection points can beexecuted as punctual (e.g. welding or gluing points) or linear. Anincreased torsional resistance can be achieved by the base and also thelegs of the interconnected rails each having joining points. The railstypically consist of bent steel sheet. The inner attachment rail canespecially be constructed as a U-profile or as a hollow profile or as aD-profile or similar.

A telescopic extension is formed from at least two rail extensions ofthe same type which are joined together by the backs of their attachmentrails.

These reinforcements are equally suitable for rail extensions (so-calledpartial extension) and for multi-part telescopic extensions (so-calledfull extension) which make it possible to achieve a horizontal orvertical displacement of an extendable element. Either a centrallyattached rail or telescopic extension can be provided for guidance of anextendable element. Alternatively, two or more rail or telescopicextensions can be provided which are preferably attached to bothlongitudinal sides of the extendable element.

The invention is explained in detail in the following with reference toan exemplary embodiment with reference to the appended drawings. In thefigures:

FIG. 1 is a cooker with a horizontal rail extension according to theinvention,

FIGS. 2 and 3 each show a cooker with a vertical rail extension,

FIGS. 4 and 5 each show a schematic detailed view of two alternativevariants of the rail extension according to the invention,

FIG. 6 shows a schematic detailed view of a telescopic extension and

FIG. 7 is a schematic diagram of an extendable element of a telescopicextension.

FIG. 1 shows a cooker 2 in conventional design with a door 23 at thefront in the form of a front flap which can be hinged downwards.Provided on the side walls of a cooking compartment 22 are railextensions 4 which make it possible to horizontally extend an extendableelement 26, preferably a baking shelf 28 or similar. In the view shownthe rail extensions 4 are each constructed as so-called partialextensions in which a short section of the baking shelf 28 stays insidethe cooking compartment 22. A longer extension path of the baking shelfcan be achieved with a so-called full extension which has telescopicextensions in each case instead of simply extendable rail extensions.This variant of an extension is described in detail with reference toFIGS. 6 and 7.

FIGS. 2 and 3 each show an alternative design of a cooker 2 which has adoor 23 on an underside 24 of an oven housing 21 which can be displacedvertically downwards and thereby makes it possible to have access to ashelf 28 for food (see FIG. 3). Instead of the rail extensions 4 shownin FIGS. 2 and 3, the downward-extendable element 26 can also beconstructed as extendable by means of a telescopic extension, as isdescribed in detail in FIGS. 6 and 7.

FIG. 4 shows a schematic detailed view of a first variant of a railextension 4 according to the invention, viewed from above. A U-shapedouter rail 41 is affixed to a side wall or other fixing point of an ovenhousing 21. The outer rail 41 is connected by a base 42 of its U profileto the oven housing 21 by means of a screwed, glued, riveted and/orwelded joint. The legs 43 of the U-profile of the outer rail 41 areconfigured as running surfaces for rolling elements or balls 48 of ananti-friction bearing 47. They therefore have a slightly outwardlycurved contour. For stiffening the outer rail 41 an attachment rail 49is provided inside its U-profile, whose legs 51 are connected to theinsides of the legs 43 of the outer rail 41 and whose base 50 isconnected to the base 42 of the outer rail 41. These connections can beconfigured as welded, glued, riveted and/or screw connections asdesired. An elevated torsional resistance can be achieved by providing aseries of connecting points in the cross-section and not only, forexample on the base 42 of the outer rail 41 between the base 50 of theouter attachment rail 49.

Whilst the rolling elements 48 of the anti-friction bearing 47 aresupported internally on the legs 43 of the outer rail 41, on the outsidethey guide a sliding rail 44 whose two legs 46 are each slightly curvedinwards and in this way provide for a fixing of the balls 48 on theirprovided races. One base 45 of the sliding rail 44 is connected to abase 53 of an attachment rail 52 whose legs 54 abut against the legs 46of the sliding rail or are connected to this. These connections can alsobe configured as welded, glued, riveted and/or screw connections. Theattachment rail 52 provides for a stiffening of the sliding rail 44 andprevents its distortion during an extension of the rail extension 4.Likewise, the outer attachment rail 49 provides for a stiffening andstabilisation of the outer rail 41.

The balls or rolling elements 48 are preferably guided in a cage 55which ensures a uniform spacing of the balls from one another. Dependingon the desired usage, the anti-friction bearing can have greaselubrication which is resistant to the temperatures prevailing in thecooking compartment. If the cooker is operated even temporarily in apyrolysis mode, such grease lubrication is unsuitable since it cannotwithstand the typical pyrolysis temperatures of around 500° C. In thiscase, for example, rolling elements and/or races made of ceramic orhaving a ceramic coating can be used.

FIG. 5 shows a schematic detailed view of a second variant of the railextension 4 according to the invention. Affixed to a side wall of theoven housing 21 is an outer rail 41 with a D-shaped hollow profile. Theouter rail 4 is connected by a back 56 of its D-profile to the ovenhousing 21 by means of a screwed, glued, riveted and/or weldedconnection. The legs 43 of the D-profile of the outer rail 41 areconfigured as in the first variant as races for balls 48 of theanti-friction bearing 47 and thus have a slightly concave profile.

The outer rail 41 is very rigid towards torsion and bending as a resultof its closed profile. The closed profile is achieved by a base 50 whichconnects the legs 43, which in this variant corresponds to the outerattachment rail 49 according to the first variant.

The guidance of the extendable element 26 with the aid of theroller-mounted sliding rail 44, which is reinforced by the attachmentrail 52, corresponds to the first variant which has already beendescribed with reference to FIG. 4. The reasoning put forward thereapplies similarly here.

FIG. 6 shows a detailed view of a telescopic extension 6 which issubstantially constructed of two interconnected rail extensions 4according to FIG. 4. In this case, two attachment rails 52 areinterconnected by the backs of their bases 53 so that the sliding rails44 can be displaced longitudinally over the left portion of thetelescopic extension 56 towards the oven housing 21 and the rightportion of the telescopic extension 6 can be displaced longitudinallywith the extendable element 26 towards the two sliding rails 44. Theremaining structure corresponds to that of the rail extension 4according to FIG. 4. In the same manner, a telescopic extension can beachieved with combined rail extensions according to the second variant(FIG. 5). A combination of both variants in a telescopic extension canalso be meaningful.

FIG. 7 illustrates in a perspective schematic view an extended telescopeextension 6 in which the outer rail 41 is affixed to the oven housing21. The attachment rails 52 displaced downwards with respect to theouter rail 41 in turn hold the outer attachment rail 49 affixed thereto,to which the extendable element 26 is affixed. A support 28 of theextendable element 26, which points towards the front at right angles,causes possible bending of the rail or telescopic extension 6 undergreater loading by a correspondingly heavy baking shelf, which islargely prevented by the outer attachment rails 49 or attachment rails52 which are additionally present. The two arrows shown indicate thisloading.

Basically, a single telescopic extension or rail extension can beprovided for the support and displaceability of a baking shelf.Frequently, however, two parallel extensions are provided which arearranged on both sides of the door and ensure its better guidance.

Reference list

-   2 cooker    -   21 oven housing    -   22 cooking compartment    -   23 door    -   24 underside    -   25 front    -   26 extendable element    -   27 longitudinal side    -   28 support/baking shelf-   4 rail extension    -   41 outer rail    -   42 base (outer rail)    -   43 leg (outer rail)    -   44 sliding rail    -   45 base (sliding rail)    -   46 leg (sliding rail)    -   47 anti-friction bearing    -   48 rolling element/ball    -   49 outer attachment rail    -   50 base (outer attachment rail)    -   51 leg (outer attachment rail)    -   52 attachment rail    -   53 base (attachment rail)    -   54 leg (attachment rail)    -   55 cage    -   56 back side-   6 telescopic extension

1-16. (canceled)
 17. A rail extension for the horizontal or verticalextension of an element such as a cupboard element, a baking shelf or anoven door of a cooking appliance or similar device, the extensioncomprising: at least one outer rail of bent sheet metal; a sliding railof bent sheet metal that partially surrounds said outer rail; ananti-friction bearing by which said sliding rail can be displace alongsaid outer rail; and an outer attachment rail connected to andreinforcing at least one of said outer rail or an attachment railconnected to said sliding rail.
 18. The rail extension according toclaim 17, including said outer rail and said sliding rail each having apair of legs and said anti-friction bearing includes at least onerolling element which slides between one of said legs of each pair oflegs of said outer rail and said sliding rail for mutual guidance ofsaid outer rail and said sliding rail.
 19. The rail extension accordingto claim 18, including said rolling element formed by a plurality ofcage-mounted balls, roll or rollers.
 20. The rail extension according toclaim 17, including said outer rail has a U-shaped profile.
 21. The railextension according to claim 17, including said outer attachment railhas a U-shaped profile.
 22. The rail extension according to claim 17,including said outer rail is connected to said outer attachment rail byat least one of welding, riveting, screwing or gluing.
 23. The railextension according to claim 17, including said outer rail is formedwith a closed hollow profile.
 24. The rail extension according to claim23, including said outer rail is formed with a D-shaped profile.
 25. Therail extension according to claim 17, including said sliding rail andsaid attachment rail are formed with a U-shaped profile.
 26. The railextension according to claim 17, including said sliding rail isconnected to said attachment rail by at least one of welding, riveting,screwing or gluing.
 27. The rail extension according to claim 17,including the horizontal or vertical extension element has a pair oflongitudinal sides and each of said sides includes at least one railextension connected thereto to form a partial extension.
 28. Atelescopic extension for the horizontal or vertical extension of anelement such as a cupboard element, a baking shelf or an oven door of acooking appliance or similar device, the telescopic extensioncomprising: a pair of interconnected rail extensions; each of said railextensions including; at least one outer rail of bent sheet metal; asliding rail of bent sheet metal that partially surrounds said outerrail; an anti-friction bearing by which said sliding rail can bedisplace along said outer rail; an outer attachment rail connected toand reinforcing at least one of said outer rail or an attachment railconnected to said sliding rail; each said attachment rail having a flatbase section; and said flat base sections of said pair of attachmentrails joined together to form said interconnection of said railextensions.
 29. The telescopic extension according to claim 28,including each of said attachment rails are formed with a U-shapedprofile.
 30. The telescopic extension according to claim 28, includingsaid attachment rails are joined together by at least one of welding,riveting, screwing or gluing.
 31. The telescopic extension according toclaim 28, including the horizontal or vertical extension element has apair of longitudinal sides and each of said sides includes at least onetelescopic extension connected thereto.
 32. The telescopic extensionaccording to claim 31, including forming a full extension of saidextension element.